Organophosphorus compounds have numerous and varied applications, for example, in herbicides, insecticides, fertilizers, flame retardants and plasticizers and as precursors for the synthesis of other organophosphorus compounds. Cyanophosphonates and their derivatives are of particular interest due to their versatility in synthetic pathways and a wide range of chemistries can extend from both the phosphorus and cyano moieties.
McKenna et al., J. Am. Chem. Soc. 117:7285-86 (1995), describe the preparation of orthophosphoric acid, phosphorocyanidic acid and the dicyclohexylamine salt of phosphorocyanidic acid. The McKenna synthesis of phosphorocyanidic acid involved a multi-step pathway with acid catalyzed hydrolysis of Z-hydroxyiminophosphonic acid tetrasodium salt and had reportedly low yields. McKenna et al. also disclosed the preparation of phosphorocyanidic acid from dimethyl phosphorocyanidate by silyldealkylation with trimethylsilylbromide followed by quenching with methanol. The dicyclohexyl ammonium salt was also isolated from the acid by treatment with dicyclohexylamine. McKenna also reportedly prepared a half acid, half salt sodium methylcyanophosphonate by the reaction of sodium iodide and dimethylcyanophosphonate in acetone. McKenna also disclosed the preparation of orthophosphoric acid by acid hydrolysis of E-hydroxyiminophosphonic acid tetrasodium salt.
Shiori et al., Tetrahedron 32:2211 (1976), disclosed the preparation of dimethylcyanophosphonate from trimethylphosphite and cyanogen bromide. Diethylcyanophosphonate is commercially available from Aldrich Chemical Co. in 93% purity.
Tung et al., Hua Hsueh Hsueh Pao (Acta Chimica Sinica) 31(3):199-202 (1965), disclosed the preparation of O,O'-dialkyl phosphoryl cyanides by the reaction of sodium cyanide with dialkylphosphonates in the presence of carbon tetrachloride. Tung et al. reports that the method was used to prepare dimethylphosphoryl cyanide, diethylphosphoryl cyanide, di-n-propylphosphoryl cyanide and di-iso-butylphosphoryl cyanide.
There exists a need for novel cyanophosphorus compounds and methods for their preparation to enable the preparation of organophosphorus materials with a variety of beneficial uses.